Certified to reduce 99% of lead as well as other potentially harmful contaminants, KitchenAid™ filters offer convenient, filtered water for you and your family. For the cleanest water, replace your KitchenAid™ filter every 6 months (or 200 gallons). KitchenAid™ Ice & Water Refrigerator Filter 4 replaces W11256135 & W11311161